1. Field of the Invention
The invention relates generally to powered surgical cutting instruments for endoscopic use. More particularly, the invention relates to elongated surgical instruments in which an elongated hollow inner tube is rotatably received within a stationary, elongated hollow outer tube, both inner and outer tubes having cutting apertures at their distal ends which cooperate to resect or otherwise affect tissue during endoscopic surgical procedures.
2. Description of the Prior Art
The use of both liposuction and lipectomy devices is known although prior to this invention the use of liposuction, i.e., manual instruments, has been preferred because of deficiencies associated with the prior art lipectomy, i.e., powered systems.
In conventional liposuction procedures, an elongated cannula having a side facing aperture at its distal tip is connected at its proximal end to a source of suction. The cannula is passed through an incision in the body in order to place its distal tip adjacent a body region targeted for removal of fat or adipose tissue. Such manual procedures require vigorous back and forth motion of the cannula in order to avulse fat tissue and aspirate it through the lumen of the cannula.
A powered, lipectomy device is described in U.S. Pat. No. 4,735,605 (Swartz), incorporated by reference herein, in which a conventional manual liposuction cannula is modified by combining it with a rotating inner tube having a cutting edge in the form of a spiral slot in its distal end. The rotation of the slot of the inner tube under the elongated side-facing aperture or window of the cannula creates a "traveling hole" by which tissue sucked into the aperture is resected and aspirated through the lumen of the inner tube with less difficulty than manual procedures. Such powered lipectomy devices have not been widely accepted among surgeons although elongated powered surgical instruments are known to be used in other surgical procedures such as arthroscopy, or more generally, endoscopy.
The term "endoscopic" as used herein refers to closed surgery in which access to the surgical site is gained via one or more portals in the body (natural or artificially created) whether or not one uses a visualization instrument such as an elongated scope or camera. Thus, the lipectomy and liposuction procedures described herein will occasionally and interchangeably be referred to as endoscopic procedures. It will be understood, however, that both lipectomy and liposuction procedures may be performed as open procedures and the invention is intended to provide such flexibility. Open liposuction would, however, require greater suction and the invention enables procedures to be performed with less suction.
Some conventional endoscopic surgical resecting instruments for use in closed surgery (known as shavers or blades) are somewhat similar to the Swartz device: i.e., a straight, elongated stationary outer tubular member having a straight, elongated rotating inner tubular member concentrically disposed in the outer tubular member. The distal ends of the tubes may be formed with a variety of cutting edges and windows to achieve particular functions. Therefore, while many different configurations of inner and outer members are known, those configurations most similar to the Swartz device and most adaptable to use in removing fat or adipose tissue are the ones having a side facing window in the outer member with a cutting edge on the inner member that can resect tissue presented in the outer cutting window. An example of a lipectomy device which is similar to conventional side-facing arthroscopic shavers is shown in U.S. Pat. No. 4,815,462 (Clark). However, known side-facing rotatable shavers are not entirely suitable for use in lipectomy or liposuction procedures; they are generally either too aggressive or ineffective for adipose tissue.
Furthermore, it has been found that a preferred surgical lipectomy procedure, whether open or closed, incorporates lipectomy interchangeably with liposuction. Lipectomy is defined herein as resecting adipose tissue from a surgical site either under direct vision (i.e., open) or endoscopically (with or without visualization) while liposuction is defined herein as aspirating adipose tissue from the site. No known device is optimized for use in both lipectomy and liposuction procedures. Thus, it is an object of this invention to provide a single endoscopic instrument suitable for use as a lipectomy device and as a liposuction device.
There is a need to improve the design of prior art endoscopic surgical shavers to optimize them for use in lipectomy or liposuction procedures. It is generally preferable to sometimes avulse tissue from a site (as in liposuction) rather than resect it (as in lipectomy) in order to avoid inadvertently injuring adjacent structures (e.g. neurovascular bundles, etc.). However, the simple avulsion provided by conventional liposuction cannulas is sometimes too cumbersome, inefficient and traumatic while the resection provided by conventional shavers is sometimes too traumatic and risky.
Accordingly it is an object of this invention to produce a surgical cutting instrument adapted for use in lipectomy and liposuction procedures.
It is also an object of this invention to produce a surgical instrument capable of being used as a conventional manual liposuction cannula as well as a powered lipectomy resecting instrument.
It is another object of this invention to produce a surgical instrument optimized for use in lipectomy and liposuction procedures.